This invention relates generally to refrigerator air circulation systems, and more particularly to a motorized air baffle for controlling the flow of air within a fresh food compartment of a refrigerator.
Conventional dual compartment refrigerators of the forced air circulation type utilize a single evaporator and an evaporator fan for cooling a freezer compartment thereof. The freezer compartment is coupled by a plurality of air passages through a divider wall to a fresh food compartment. An air baffle is located within the fresh food compartment air inlet passage wherein the baffle is operable to control the passage of refrigerated air into the fresh food compartment. In such a conventional refrigerator, if the refrigeration unit is operating, then the evaporator fan forces air flow across the evaporator coils and out the top of the freezer into a scoop which directs air to the fresh food compartment, past the baffle.
Typically, the baffle is manually adjustable for determining the proportional flow of air into the fresh food compartment during the freezer cooling cycle. However, various systems have been provided for automatically operating the baffle for providing improved control over the fresh food compartment temperature.
U.S. Pat. No. 4,924,680, to Janke et al., discloses a controllable baffle for a refrigeration apparatus. The baffle includes a fixed plate and a movable plate each having corresponding apertures therethrough for permitting the control of air flow to a fresh food compartment. The movable plate is slidably mounted to the fixed plate permitting straight line reciprocal motion of the movable plate with respect to the fixed plate. A solenoid actuator is provided for driving the movable plate.
U.S. Pat. No. 4,282,720, to Stottmann et al., discloses a refrigerator fan control for a refrigerator. This reference shows a rotatable air valve or baffle. The valve rotates between its open and closed positions of 90.degree. by a solenoid that is momentarily energized. The energization of the solenoid effectively rotates the valve 45.degree. in each direction of its armature reciprocal movement.
U.S. Pat. No. 4,920,758, to Janke et al., discloses an air circulation system for a refrigeration apparatus having a controllable baffle for selectively opening or closing dual output ports. The baffle includes a rotatable disk having open portions and closed portions. A motor is coupled to the disk for selectively rotating the disk so that its respective open portions are in selective alignment or disalignment with the dual output ports such that air circulation within the refrigerator is controlled.
One problem with all of the baffle systems as described above is that moisture can accumulate on the baffle during a defrost cycle. The amount of moisture depends in part on the ambient humidity. Colder air from the evaporator coils can cause any moisture accumulated on the baffle to freeze. The resulting ice prevents free movement of the baffle which may result in undesirable effects such as overcooling of the fresh food compartment.
U.S. Pat. No. 4,903,501, to Harl, discloses a controllable baffle for a refrigeration apparatus wherein means are provided for preventing freeze up of the baffle. The baffle includes a fixed plate and a movable plate each having corresponding apertures therethrough for permitting the control of air flow to a fresh food compartment. The fixed plate is provided with a heating device molded therein which is operable to maintain the fixed plate above the freezing temperature to prevent moisture from freezing thereon. Additionally, spacer means are provided for maintaining the movable plate in spaced relation with the fixed plate for minimizing moisture which may bridge between the plates and freezer. A solenoid actuator is provided for driving the movable plate.